url=http://c.biancheng.net/shell/
echo $url
name="C语言中文网"
echo $name
author='演唱少女'
echo author
#修改变量的值
url="hhhhh"
echo $url

echo ${url}

url="http://c.biancheng.net"
website1='C语言中文网：${url}'
website2="C语言中文网：${url}"
echo $website1
echo $website2

myUrl="http://c.biancheng.net/shell/"
readonly myUrl
myUrl="http://c.biancheng.net/shell/"
echo $myUrl
unset myUrl
echo $myUrl
